Fibrous materials such as, wool, wood, paper, rockwool, fiberglass and cellulose, including cellulose made from recycled newspapers and other paper, are today commonly used for insulating buildings, homes and other structures and things. The fibrous material is typically conveyed through air hoses wherein the air travels at a sufficiently high velocity for carrying the fibrous insulation material therethrough and to the location being insulated such as, for example, attics and walls. Essentially, the fibrous material is mixed or is otherwise introduced into the high velocity air stream traveling through the hose such that the fibrous material is carried through the hose and to the location being insulated.
When insulating a horizontal surface such as an attic floor, the operator directs the air and fibrous insulation toward the cavities being filled, for example, between joists, such that, as the air exiting the hose dissipates, the fibrous insulation settles into the cavity being insulated. In some horizontal applications water is injected into the conveying hose near the machine to activate dry adhesives mixed with the insulation fibers to form a stabilized homogeneous mat in attac areas. For insulating vertical surfaces such as in stud wall cavities, an adhesive is used for causing the fibrous insulation material to essentially be adhered or stick to the surface where needed and to also stick to other fibrous insulation so as to build up the insulation material to a desired thickness. In this regard, an adhesive mist can be sprayed near the insulation conveying hose exit opening such that as the insulation travels from the end of the hose to the vertical surface it is mixed with the adhesive causes the insulation to stick as needed. Alternatively, dry adhesives are mixed and conveyed with the fibrous insulation through the conveying hose and a proper catalyst mist, typically water, is provided at the end of the hose such that the dry adhesive will react with the catalyst and provide adhesion for causing the fibrous insulation material to again stick to the vertical surface and/or itself for building up the insulation material to a sufficient desired thickness.
As can be appreciated, for the operator to properly direct and apply the fibrous insulation as it is exiting the conveying hose, the velocity of the air and insulation mixture must be correct and the conveying system and hose should not be subject to plugging. In this regard, to maximize efficiency, it is desirable to convey the greatest possible amount of insulation per given volume of air. However, if the operator attempts to convey too much insulation such that the air velocity is insufficient, the conveying hose and other parts of the system are subject to plugging and the applied density of the insulation can be adversely affected. On the other hand, if the air velocity is too great, the operator is unable to control the placement of the insulation causing, as it is referred to in the industry, a “dust storm”. Additionally, in the event the insulation is being placed on vertical surfaces, insulation traveling at the higher velocity tends to be more densely packed as it is built up to the desired thickness, causing the application cost to increase and the insulation value to decrease.
Achieving the proper air to insulation mixture and rate of delivery of the insulation is yet further complicated by the fact that fibrous insulation feeders are unable to always provide a perfect air to insulation feed rate and mixture; the friction loses in the conveying hose change as the conveying hose length is increased or decreased as needed by the operator; the required head pressure for conveying the insulation through the hose changes as the operator moves the exit opening of the conveying hose vertically up and down and/or between floors of a building or house, etc.
A schematic diagram of a prior fibrous insulation conveying system is shown in FIG. 1 and generally designated by the numeral 10. Prior art conveying system 10 includes a blower 12 drawing air from the atmosphere at its inlet 14 and providing an air flow stream under pressure at its outlet 16. Outlet 16 is typically connected via a duct 18 and a directional check valve 20 to a fibrous insulation feeder 22. The fibrous insulation feeder 22 includes an air inlet 24, a product inlet 26 for receiving fibrous insulation, and an air and product mixture outlet 28 connected to a conveying hose 30. A slide gate 32 is provided for selectively setting the rate of product being fed into the airflow stream and out through the air and product mixture outlet 28. A pressure relief valve 34 and an air bleed valve 36 are connected between the air flow duct 18 and the atmosphere. Air bleed valve 36 includes a handle 38.
For use of the prior art fibrous insulation conveying system 10, the operator initially engages the blower 12 and then adjusts the handle 38 of air bleed valve 36 for setting the desired air flow velocity. The slide gate 32 is then set to a fixed position for a desired insulation feed rate. However, in view of the varying resistance and other variables, any significant back pressure that may be experienced in the conveying hose 30 causes plugging and substantial amounts of down time for cleaning and resetting the system. To decrease plugging, operators are left with no alternative but to reduce the average material feed rate which, unfortunately, results in underutilization of the equipment capacity and decreased efficiency in the application of the insulation.
Some of the problems-associated with the prior art fibrous insulation conveying systems of the character shown in FIG. 1 were addressed in prior U.S. Pat. No. 6,092,747. The conveying machine of that patent includes a variable speed blower for providing the operator additional control in adjusting the air flow velocity. Additionally, the pressure in the air flow duct between the blower and feeder is monitored and, in response thereto, the insulation feed rate is controlled thereby helping to prevent plugging of the conveying hose and system. Although this conveying machine is a significant improvement, the maximum insulation feed rate is limited by the preset air flow velocity and, to prevent possible plugging as a result of varying resistance or back pressure in the conveying hose, it has been found that operators, nevertheless, reduce the feed rate sufficiently for the preset desired air flow velocity thereby, again, resulting in underutilization of the equipment and decreased efficiency in the application of the insulation.
When applying fibrous insulation material to vertical surfaces such as vertical stud wall cavities, as the insulation is built up, the resulting outer surface is rough and not level with the inner stud edges or face. The resulting rough insulation surface is typically leveled to the stud face and the excess removed material falls to the floor wherefrom it is recovered and reused. This excess fibrous material is typically vacuumed, separated from the air, and then reused alone or by mixing with virgin fibrous insulation and running such material back through the insulation feeder. A vacuum and separator system of this character is shown, for example, in U.S. Pat. No. 6,364,579. When insulating, a conveying system of the character shown in prior U.S. Pat. No. 6,092,747 and a vacuum and separating system of the character shown in U.S. Pat. No. 6,364,579 are typically simultaneously used side by side.
Accordingly, a need exists for fibrous insulation conveying systems which continuously maximize the insulation feed rate while providing the operator the desired control of the air flow velocity and feed rate for the particular application while preventing plugging and, further, providing a system for conveying and vacuuming fibrous insulation material efficiently and relatively inexpensively.